A bookbinding system comprising: an image forming apparatus (A); and a bookbinding apparatus (B); wherein both the image forming apparatus (A) and the bookbinding apparatus (B) include a communication section respectively, for transmitting information from the image forming apparatus (A) to the bookbinding apparatus (B); the bookbinding apparatus (B) comprises a coating section (60) for coating adhesive on a stack of sheets, a replenishing section for replenishing adhesive to the coating section (60), and a controller (CD2) for controlling the replenishing section; and the controller (CD2) controls replenishment rate of the adhesive by the replenishing section, based on information transmitted from the image forming apparatus (A) through the communication section.